Do you yearn for the burn? It seems we can’t get enough of chilli peppers, with ever spicier varieties bred to satisfy our insatiable appetite for these pungent fruits.
Let's dial up the heat by delving into the hotly contested world of super-spicy chillies, and explore the best ways to grow hot peppers that will literally leave you breathless!
Super-Spicy Chillies to Grow
We all know that chilli peppers vary in heat, from the playful Pimiento to the positively painful Carolina Reaper! But did you know that there’s a scale to measure the heat level of chilli peppers? It’s called the Scoville Scale and it travels from zero (for a sweet bell pepper) all the way up to 15 million SHU for pure capsaicin, the compound responsible for that spicy heat.
![Scotch Bonnet chillies]()
Scotch Bonnet chillies have a real kick!
Those Pimientos start at around 300 Scoville Heat Units, while Anaheim peppers register 1,500. Some of our most popular hot sauce chillies come in next – Sriracha at around 2,200 units, and Tabasco at 3,500. Now we’re starting to get somewhere! Jalapenos register a rather warm 5,250 units, Serrano peppers 16,500, while the Thai chilli (a.k.a. Bird’s Eye chilli) ratchets up the heat to 75,000, leaving cayenne peppers trailing at a pathetic 40,000!
Okay, so now it’s time to buckle down for our hotlist – the exclusive club, the spicy elite! Coming in at 225,000 SHU is the Scotch bonnet, while Habaneros register up to a tread-with-care 445,000. Ghost Peppers? They’re an astonishing one million units! Seven Pot Primos reach a searing 1.5 million, while the infamous Carolina Reaper, previously the official record holder, comes in at an eyewatering 1.64 million! The unstoppable quest for heat never falters, however, with the recently bred Pepper X topping out at nearly 2.7 million SHU – ouch!
![Carolina Reaper chillies]()
Fear the (Carolina) Reaper
The Best Potting Mix for Chilies
To get your feisty chillies off to a great start, you’ll need a great growing medium. I like to use equal quantities of multi-purpose peat-free potting mix with coir, plus a few handfuls of vermiculite thrown in for good measure. Peppers can’t stand being too wet, and this mix will drains through really well, while also holding onto enough moisture to help plants thrive.
Pot your chilli plants on into progressively larger pots as their roots fill them, ending up with a pot of anywhere between 2-5 US gallons (8-20 litres). Bigger containers will grow bigger plants and will need less watering, but will take more potting mix to fill, so it’s up to you which way to call it.
![Watering a chilli pepper plant]()
For the spiciest fruits, avoid overwatering
Chilli Pepper Growing Tips
Chilli peppers HATE sitting in the wet. I can’t emphasise that enough – they really hate it! Too much water can disrupt the flow of nutrients around the plant, causing growth problems and weakening the plant so they’re vulnerable to attack from pests and diseases. But worst of all, too much water literally waters down the capsaicin in the developing fruits, quashing all those dreams of super-spicy chillies.
These plants thrive in hot, dry conditions, so water just enough to keep plants ticking over. You can even let them wilt a little, especially later in the growth cycle when the fruits are maturing. Avoid watering in the hours leading up to harvest if you want spicier fruits.
Water on a dilute liquid feed regularly as they grow, and then once the first flowers appear switch to a feed that’s higher in potassium, such as a tomato feed. If you’re really keen, you could even try one of the feeds sold specifically for pepper plants.
![Bird's eye or Thai chillies]()
Spicy chillies love warm weather
Chilli peppers – especially the hottest types – love warm weather. They’re happy up to around 90ºF (32ºC), so in my temperate climate that means protecting plants from cold weather at all costs. The solar heating of a greenhouse is ideal, and will help to keep things a little warmer when it’s cool and cloudy too.
When it does get hot, open up all of the greenhouse windows and doors to ensure a good throughflow of air. Good airflow is important in the fight against disease. Other things you can do to keep plants in fine fettle is to leave plenty of space between them and remove any dead leaves and other detritus so you’ve got a good, clean growing environment. Of course, if you’re in a hot climate, just grow them outdoors!
Check your chillies, especially greenhouse-grown plants, regularly. Act on pests quickly, encouraging natural predators such as parasitic wasps and ladybirds as much as possible. Leave the greenhouse door open, and coax them in by planting flowers in there too.
![Harvesting chillies]()
Handle with care!
Harvesting Chilli Peppers
Your chilli peppers are ready once they have taken on their final colour and full size. They’ll be at their spiciest once they’re fully ripe. Be sure to cut rather than tug them off the plant to avoid any damage, and wear gloves – or at least make sure not to rub your eyes afterwards, because you’ll really regret it!
